.I have no idea how fit for purpose the product is but have a look at this ResellerRatings page for "Buy.com".

Bob.

hhhmm, that's strange, I have ordered many times from them and had no problems. I got an 8 gig flash drive for 14 dollars from them, and it arrived within a week. They're one of Amazon.com's biggest rivals.

As far as purposes, I guess it'll be good if you need to backup and your laptop is nowhere near you. Or too bulky to drag along, example if you're going to a trip for a couple of days, and you decided to leave your laptop at your hotel.